In order to assess the effects of reperfusion therapy on right ventricular myocardial infarction, we studied at necropsy the hearts from 51 patients who died after receiving intravenous recombinant tissue plasminogen activator for left ventricular myocardial infarction as part of the TIMI trial. Right ventricular infarction occurred in none of 29 patients with anterior wall left ventricular infarction, and in 8 of 22 patients (36%) with inferior wall left ventricular infarction. Of the 22 patients with inferior wall infarction, the 8 patients with right ventricular infarction were compared to the 14 patients without right ventricular infarction. Patients with right ventricular infarction had a longer mean interval from tissue plasminogen activator infusion to peak creatine phosphokinase level (19 hr vs 11 hr, p less than 0.03), a lower incidence of hemorrhagic necrosis (2 of 8 [25%] vs 10 of 14 [71%], p less than 0.04), and higher incidence of luminal thrombus in the infarct-related coronary artery (6 of 8 [75%] vs 3 of 14 [21%], p=0.054). Each of these findings is associated with the absence of coronary reperfusion. Thus, it appears that successful reperfusion following acute left ventricular myocardial infarction is associated with a decreased incidence of concomitant right ventricular myocardial infarction.